Draft damper closer



March 13, 1934. c. M. SE LBY 1,950,755

DRAFT DAMPER CLOSER Filed Feb; 24, 1931 patented Mar. 13, 1934 DRAFT DAMPER o osER Charles M. Selby, Holland, Mich, assignor to Holland Furnace Company, Holland, Mich., a corporation of Michigan Application February 24, 1931, Serial No. 517,703

7 Claims.

This invention relates generally to a flexible power transmitting element and more particularly to a chain control system for furnaces whereby the several doors may be properly operated with respect to each other.

As is well known to those skilled in this art, furnaces of this character are provided with a feed door, through which the fuel is inserted, an ash-pit door therebelow and a check draft door, the check draft door being positioned on the smoke pipe which leads upwardly to the stack.

Flexible elements or chains lead from both the check draft door and the ash-pit door and provide means whereby these two doors may be controlled manually or automatically. Such control takes care of the normal operation of the furnace. However, when the furnace is fueled, it is necessary to open the feed door and when this is done the flames from the furnace are liable to issue therefrom. Hence, it is desirable, and such is the present day practice, to close the check draft door and the ash-pit door, or at least one of them, whenever the feed door is opened, in order that the combustion within the furnace may be temporarily diminished whereby there will be no danger of the flames and smoke issuing through the feed door.

One of the principal objects of my invention is to provide control means whereby the manipulation just recited may be automatically accomplished. In other words, when the feed dooris open the ash pit door and the check draft door will be closed. Also, it is to be noted that no interference is had with the manual or automatic means which normally controls these doors.

Briefly described, my inventionconsists of a supporting frame having two sets of pulleys in alined relationship, these pulleys being adapted toreceive the two flexible elements therethrough. The flexible elements referred to are those leading from the check draft door and the ash pit door and after passing through the alined set of pulleys these elements terminate in a free end by which they may be either manually or automatically controlled. I provide a guiding device, which may consist of a double pulley, intermediate of the two previously referred to set of pulleys and this latter single guiding pulley is movable whereby the paths of the control chains may be varied. A third chain leads from the movable guiding means to the feed door and spring means are fastened to the movable means which supports the guiding pulley thus keeping this third chain taut. Hence, when the feed door is opened, the guiding pulley will be lifted out of its normal position due to the action of the spring and consequently, when the paths of the other two chains are shortened, the check draft and the ash pit doors will be closed.

In some furnace installations it is not necessary that both the ash pit door and the check draft door be closed and obviously my invention might be readily applied to an installation of this character by simply omitting the chain which leads from the ash pit door.

The operation of such a control would be substantially the same as that already described.

Further objects, and objects pertaining to the details and economies of construction and operation of my invention will definitely appear from the detailed description to follow.

In the drawing:-

Fig. 1 is a perspective view of a furnace having my novel control system or means attached thereto.

Fig. 2 is a side view of the chain guiding unit whereby the paths of the two chains may be shortened, the dotted line showing the posi tion of the pivoted lever when such occurs.

Fig. 3 is a view taken along the line 33 of Fig. 2.

Fig. 4 is a view in cross section taken horizontally through the front of the furnace just above the door.

Similar numerals refer to throughout the several views.

Referring particularly to Figs. 1 and 4, 10

similar parts indicates the furnace proper, 11 the smoke pipe leading therefrom, 12 one of the hot air pipes leading from near the top thereof, 13 the feed door through which fuel is fed into the furnace and 14 the ash pit door.

forth.

The ash pit door 14. opens into the box-like casting 22, which may be integrally formed with the front plate 15. The door 14 is hinged to the casting 22 as indicated at 23.

bis control element or chain 30 is attached to,

the door 14 and extends upwardly as shown in Fig. 1.

A check draft door 24 is hinged onto the casting 25 as at 26 and a chain 40 extends therefrom. The control chains 30 and are suitably guided by means of sheaves or pulleys 27, which are diagrammatically shown, and terminate in rings 31 and 41, respectively, these rings being hooked over projections 32 and 42 respectively. Thus, the doors 14 and 24 may be held open as desired.

Referring now particularly to Figs. 2 and 3, indicates a wooden base which has depending strips 51 fastened thereto. Angle members 52 are bolted to the opposite sides of the strips 51 whereby a slight space is provided therebetween, this space serving to admit a lever 53 therebetween, this lever being pivoted as at 54. Bolts 55, on either side thereof, serve as stops therefor and thus prevent extensive swinging movement of the lever. A coiled spring 56 extends from the top of the lever to one of the depending strips 51 as clearly shown in Fig. 2. This spring tends to rotate the lever 53 so that it will assume the position as shown in dotted lines in Fig. 2, this position being such that the chains 30 and 40 have their paths shortened as will later be set forth.

A guiding apparatus or double pulley 57 is mounted at the lower end of the lever 53 and the two chains 30 and 40 thread therethrough. A ring 58 is fixed to the lower end of the pulley member 57 and the chain 20, previously mentioned, connects thereto.

Double pulleys 60, similar in construction, are attached to the angle members 52 in alined relationship and the chains 30 and 40 extend therethrough as clearly shown in Fig. 2 of the drawing.

The wooden strip 50, which serves as a supporting means for the several sets of pulleys just recited, is fastened to the joist of the floor '70. Thus a suitable permanent mounting is provided for the several pulleys.

The operation of my control system is readily understood. During the normal or ordinary op eration of the furnace the free ends of the chains 30 and 40 are either manually or automatically controlled and thus the ash pit door and the check draft door may be controlled as desired. During such manipulation the chains 30 and 40 extend through the several pulleys sothat their paths are of a maximum distance. In other words the lever 53 is in substantially a vertical position. The lever 53 is held in such vertical position due to the chain 20 which is of such a length as to remain taut when the' feed door is closed.

When the feed door is opened the chain 20 becomes slack and the spring 56 operates to pull the lever 53 to the dotted line position, see Fig. 2, and the chains 30 and 40 now become slack with the result that the ash pit door and the check draft door both close and hence prevent any draft whatsoever from passing through the fuel bed. Thus an absolute prevention is had against the issuance of either smoke or flame out of the feed door during the time which it remains open. When, however, it is closed, the lever 53 is pulled downwardly against the tension of the spring 56, the flexible chains 30 and 40 are made taut and the two draft doors return to their original open position.

Having thus described my invention I desire it to be understood that the invention is in no- I wise limited to the particular illustrative embodiment disclosed, the scope thereof being set forth in the following claims.

I claim:

1. In a furnace system having a feed door, an ash pit door, and a check draft door, the combination of a flexible element leading from the ash pit door and terminating in a free end whereby control means, either manual or automatic, may be attached therewith, a second flexible element attached to and leading from the check draft door and also terminating in a free end whereby suitable control means may be associated therewith, a supporting frame, two sets of alined double pulleys attached to said supporting frame, said first and second mentioned flexible elements extending through and being guided by said pulleys, a lever pivoted upon said frame, a double pulley fastened upon the lever and being positioned between the sets of double pulleys but out of alinement there- 95 with, said flexible elements passing through the last mentioned double pulley, a spring extending between the lever and the supporting frame, said spring tending to shift the double pulley soas to slack the flexible elements passing therethrough and permit the ash pit and check draft doors to close, and a third flexible element connected between the lever and the feed door, said last mentioned flexible element being taut and holding said spring in tension when said feed door is in closed position.

2. In a furnace system having a hinged feed door and a self-closing draft door, the combination of a flexible element extending from the draft door, means at the free end of the flexible element to pull the same whereby the draft door is operated, a supporting structure, two pulleys on the supporting structure, said pulleys receiving the flexible element on corresponding sides whereby the same is guided, a third pulley receiving the flexible element, yielding means for maintaining the third pulley substantially in alinement with the two first mentioned pulleys, flexible means leading from said third pulley to a point on said feed door spaced from its hinges and guiding means adjacent said hinges, said flexible means extending through said guiding means and being of such length as to extend said yielding means when the feed door is in closed position.

3. The combination with a furnace having a draft door, of a flexible element connected to said draft door by means of which said door may be moved, two spaced apart fixed guiding members in the path of said flexible element between 130 its ends over which said flexible element passes and a movable guiding means engaging said flexible element between said fixed guiding means and movable to a position to flex said flexible element between said fixed guiding means.

4. The combination as set forth in claim 3 in which manual operated means is provided for moving said movable guiding means.

5. The combination of elements as recited in claim 3 in which spring means is provided for 140 urging the movable guiding means to a predetermined position.

6. The combination, of elements as set forth in claim 3 but also including a fuel door in said furnace and means cooperatively associated with 5 said fuel door and the movable guiding means whereby movement of the fuel door in one direction causes operation of said movable guiding means.

7. In a furnace having a feed door and a self 160 for fastening the flexible element to the feed door so that opening of the feed door releases the flexible element and the second mentioned means to shorten the path of said chain between said guides and to permit closing of the check draft door.

CHARLES M. SELBY. 

